Ligand binding to a Ni-Fe cluster orchestrates conformational changes of the CO-dehydrogenase-acetyl-CoA synthase complex.
Ruickoldt, J., Kreibich, J., Bick, T., Jeoung, J.H., Duffus, B.R., Leimkuhler, S., Dobbek, H., Wendler, P.(2025) Nat Catal 8: 657-667
- PubMed: 40727002 
- DOI: https://doi.org/10.1038/s41929-025-01365-y
- Primary Citation of Related Structures:  
9FNC, 9FNJ, 9FO4, 9FOP, 9FOX, 9FR0, 9FR1, 9FU3, 9FU4, 9FU7, 9FU9, 9FUA, 9FUB, 9FUC - PubMed Abstract: 
Catalytic metal clusters play critical roles in important enzymatic pathways such as carbon fixation and energy conservation. However, how ligand binding to the active-site metal regulates conformational changes critical for enzyme function is often not well understood. One carbon fixation pathway that relies heavily on metalloenzymes is the reductive acetyl-coenzyme A (acetyl-CoA) pathway. In this study, we investigated the catalysis of the last step of the reductive acetyl-CoA pathway by the CO-dehydrogenase (CODH)-acetyl-CoA synthase (ACS) complex from Carboxydothermus hydrogenoformans , focusing on how ligand binding to the nickel atom in the active site affects the conformational equilibrium of the enzyme. We captured six intermediate states of the enzyme by cryo-electron microscopy, with resolutions of 2.5-1.9 Å, and visualized reaction products bound to cluster A (an Ni,Ni-[4Fe4S] cluster) and identified several previously uncharacterized conformational states of CODH-ACS. The structures demonstrate how substrate binding controls conformational changes in the ACS subunit to prepare for the next catalytic step.
- Department of Biochemistry, Institute of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany.
Organizational Affiliation: